The system PNtalk is a language and tool based on the object-oriented
Petri
nets intended for model a non-trivial distributed software system. The
distributed environment may also provide a heterogeneity of the system,
thus an interoperability between different systems (or languages). If
we can provide the PNtalk system as a tool for heterogenous modelling
and simulation, then we should first provide an interoperability
between the PNtalk and language, in which the PNtalk system is
implemented. In this time, there are two implementations -- in the
Smalltalk and Prolog environments. So, the paper presents the
interoperability of the PNtalk and Smalltalk system.